Hypertension is a disease of unknown etiology. Most investigators agree that retention of excess sodium (Na) underlies the sustained increase in blood pressure (BP) that characterizes hypertension. In children, BP elevation accompanies somatic growth in height and weight. While BP is known to be correlated to various somatic measurements, physiological mechanisms that underlie the observed associations remain unclear. Additionally, few investigations have examined whether any characteristics of somatic growth relate to the rise of BP or to the early onset of pre-hypertension or hypertension. Our preliminary data strongly suggest that the process of somatic growth is well synchronized with that of BP development. With the compelling data evidence, we propose to conduct an epidemiological study to delineate the relations among somatic growth, Na retention, and BP using data from an existing cohort of children. We hypothesize that a strong relationship of somatic growth with BP during the period of pubertal growth is mediated at least partially by increases in retention of Na. Along this line, we will examine the effects of somatic changes on measures of Na retention, and the effects of somatic growth characteristics on post-pubertal BP and the onset of pre- hypertension and hypertension. The study addresses some of the critically important but previously unanswered questions about the mechanisms of BP change during puberty. The hypotheses are derived from strong and compelling preliminary data evidence. If successfully carried out, the research may uncover early risk factors for hypertension, affording opportunities of timely interventions. To assess the post-pubertal BP and onset of pre-hypertension and hypertension, we seek to extend the follow-up period for 350 subjects in the cohort for five additional years till the subjects become adults. The existing cohort and the new extension will afford a rare opportunity to assess the linkage between somatic growth patterns in puberty and post-pubertal BP, with accommodation of Na retention. To implement, we have proposed an integrated analytical plan. By focusing on the beginnings of hypertension, before BP reaches hypertensive levels, this research provides a new approach for investigating mechanisms. While scientifically significant, the study is also cost effective because it fully utilizes the existing longitudinal data.